Boiler
E131
The E131 error code on a Baxi boiler indicates a fault with the boiler’s ignition — specifically a flame detection failure — which means your boiler has attempted to light but cannot confirm a stable flame. This is a lockout fault, so your boiler will have shut down and you’ll have no heating or hot water until it’s resolved.
What does this error mean?
Your Baxi boiler uses an ionisation sensor to detect whether the burner has successfully ignited. When the boiler fires up but the control board receives no signal confirming a flame is present — or the signal drops out too quickly — it logs E131 and locks out as a safety precaution. This prevents unburned gas from accumulating, so the lockout itself is the boiler doing exactly what it should. The root cause is nearly always either a gas supply issue, a faulty component in the ignition or sensing circuit, or a problem with the burner itself.
Est. repair cost
£100–£250 for a Gas Safe engineer diagnosis and parts (electrodes, flame sensor, or gas valve). PCB replacement can reach £300–£400+.
🔍 Likely causes
🛠️ Step-by-step fix
Check your gas supply first: try lighting a gas hob or another gas appliance. If nothing works, call your gas supplier — this is a network issue, not a boiler fault.
Check your condensate pipe (the white plastic pipe that runs outside or to a drain): if it’s frozen or blocked, thaw it with warm (not boiling) water and then attempt a reset.
Perform a boiler reset: locate the reset button on your Baxi boiler (usually a flame symbol or labelled ‘Reset’), hold it for 3–5 seconds, then wait for the boiler to attempt ignition. Refer to your model’s manual for the exact reset procedure.
If the boiler lights but E131 returns within minutes, do not keep resetting — repeated failed ignition attempts can be unsafe. Stop here.
Do not attempt to inspect or clean the ignition electrodes, flame sensor, gas valve, or PCB yourself. These components are inside a gas appliance and must only be worked on by a Gas Safe registered engineer.
If the reset does not clear the fault, or E131 returns after one or two attempts, call a Gas Safe registered engineer to diagnose the fault properly.
📞 When to call a professional
If the E131 fault returns after a single reset attempt, stop resetting and call a Gas Safe registered engineer immediately — tell them your boiler is showing an E131 lockout fault related to flame detection failure. Repeatedly resetting a boiler with a genuine ignition fault is unsafe and can mask a more serious underlying problem. If you smell gas at any point, do not attempt a reset: leave the property, avoid all switches and naked flames, and call the National Gas Emergency Service on 0800 111 999.
⚖️ Repair or replace?
A Gas Safe engineer call-out in the UK typically costs £80–£120, with parts such as ignition electrodes (£20–£50) or a flame sensor (£15–£40) on top — total repair costs usually fall between £100 and £250 depending on the fault. If your Baxi boiler is over 10–12 years old and this is not its first major fault, a repair bill approaching or exceeding £300 makes replacement worth serious consideration — a new combi boiler installed typically costs £1,800–£2,500. For boilers under 8 years old in otherwise good condition, repair is almost always the right call.